Dual indicator cathode ray tube



Aug. 16, 1955 R. F. RYcHLl-K DUAL INDICATOR CATHODE RAY TUBE 2Sheets-Sheet l Filed Dec. 27, 1946 r ff);

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Aug. 16, 1955 R. F. RYCHLIK DUAL INDICATOR cATHoDE RAY TUBE 2Sheets-Sheet 2 Filed Dec. 27, 1946 Q-v-n-Bzum|||||llllmxllllllllllllllll INVENTOR.

United States Patent @nice 2,715,725 Patented Aug'. 16, 1955 DUALINDICATOR CA'IHODE RAY TUBE Robert F. Rychlik, Dayton, Ohio ApplicationDecember 27, 1946, Serial No. 718,723

7 Claims. (Cl. 343-11) (Granted under Title 35, U. S. Code (1952), sec.266) The invention described herein may be manufactured and used by orfor the Government for governmental purposes without payment to me ofany royalty thereon.

This invention relates to signal presentation devices for use inelectronics and more particularly to an improved multiple indicatorcathode ray tube and to improved circuit arrangements with the tube thatare adapted for providing improved multiple indications of radar targetsand the like, so that from the single tube mounted in two closelyrelated circuits, A-scan and P. P. I.scan presentations can be obtainedfrom one circuit and A-scan and B-scan presentations can be obtainedfrom the other circuit.

For purposes of definition herein, radar presentations appear as rapidlytransient light traces upon the unlighted screen of a cathode-ray tubein difrerent types of scan. An A scan presentation appears as a lineartrace along the screen base line on which impressed signal amplitudesappear as deections from and at right angles to the base line andwherein the cathode-ray beam Within the cathoderay tube returns to thebase line upon cessation of signal. An accentuated A scan presentationis an A scan presentation wherein, with increase in signal amplitude,the light intensity on the screen increases in proportion to the amountof departure of the cathode-ray beam from the screen base line caused bythe signal and hence a strong signal causes not only a departure fromthe base line but also the presentation will be brighter at the deectionpeaks. In a B scan presentation the base line is moved back and forthacross the screen with vertical sweeps rising therefrom and the presenceof signals is indicated by variations in the degree of brightness of thetrace. A plan position indicator of P. P. I. scan is a mode ofpresentation wherein the sweep moves from the center of the screenradially outwardly and the sweep line is rotated radially about thecenter point of the screen and the presence of signals is indicated byvarying intensities in the brightness of the radially sweeping trace.

In the past the majority of cathode ray tubes have been divided into twoclasses: electromagnetic tubes using magnetic fields for both focusingand deflection; and electrostatic tubes using electric fields for bothVfocusing and deflection. Both classes of tubes have comprised evacuatedenvelopes and had disposed therewithin an electron gun for producing anarrow beam of rapidly moving electrons, commonly termed an electronbeam or cathode ray, that is adapted for moving from the electron gunaxially of the stem portion of the tube until it strikes a tube screenwhere it appears as a bright spot.

In the electromagnetic type of tube, the electron gun comprises acathode and heater, a control grid, a first anode or screen grid, and anaccelerating or second anode which is commonly an aquadag coating uponthe inside of the glass envelope. The electron gun of the electrostatictype of tube consists of a cathode and heater, a control grid, a firstor focusing anode and a second or accelerating anode. Control over thefocusing and accelerating of the cathode ray is exercised for thepurpose of causing inl it to be concentrated into a narrow beam and sothat both its size and velocity at the time it strikes the luminousscreen remote from the electron gun and within the evacuated envelope issuch as to cause it to produce a small luminous spot thereupon ofcontrolled intensity.

The cathode ray tubes are also provided with means for causing thedeflection both horizontally and vertically of the cathode ray so thatit sweeps the tube screen in predetermined orderly fashion. The beamdeiiecting means commonly consists of separately energized pairs ofhorizontal and vertical deiiecting coils or plates with anelectromagnetic iield maintained between the members of each pair ofcoils or plates. The magnitude and direction of the electromagneticfield so maintained determine the disposition at any instant of theelectron beam upon the tube screen. In some forms of data presentation along persistence screen is preferred and for other forms ofpresentation, a short persistence screen is preferred. Long persistencetube screen coatings require high current densities, whereas low currentdensities are suiiicient for short persistence tube screen coatings.

One type of indication that is commonly produced upon the tube screen ofan electrostatic tube is a type A-scan presentation, wherein the cathoderay is caused to describe a linear sweep defining a time base upon thetube screen under the inuence of a pair of horizontal ray deflectingplates or coils. The time base appears as a substantially horizontaldisposed line across part or all of the tube screen and may be disposedat any desired level and commonly extends across the center of the tube.In this type A-scan presentation the video output signal voltage of thereceiver part of the radar set has its output connected to the cathoderay tube, where it is applied to the pair of vertical detlecting platesor coils to cause a vertical deflection of the horizontally extendingtime base upon the tube screen with the return of each echo signal. ln atype A-scan presentation, the sweep is timed in a linear fashion so thata direct range reading may be taken from a scale associated with thetube screen.

Radar energy beamed from an antenna is highly directive and an echopulse that is received back from the target is of maximum strength whenthe antenna is pointly directly toward the target. By this invention,searching is done with a P. P. I.scan presentation and a located targetis analyzed with an A-scan presentation.

The radar antenna may be caused to rotate and to nod until a position islocated where an echo pulse produces the maximum deflection of the traceupon the screen of the cathode ray tube that is connected with theradar. The position of the sweep line including the target with respectto peripheral calibrations upon the screen during the P. P.l.presentation indicates the position in azimuth of the target. Therange or distance of the target from the radar position upon the A scaleis taken with re` spect to the zero position upon the time scale. For anormal A-scan presentation, returned echo pulses are not impressed uponthe intensity grid of the cathode ray tube. For an accentuated A-scanpresentation, returned echo pulses are impressed upon the tube intensitygrid. An indication of the elevation of the target is obtained from thenod or tilt position of the antenna dish as indicated upon the scalepart of a control boX, which is also connected with the antenna.Tactically, the usual procedure would be to operate the present systemas a P. P. I.scan to search for targets, then to switch to an A-scan forbetter resolution in the presence of jamming or other radar deceptionmethods.

For a type B-scan presentation, an electromagnetic type of cathode raytube is commonly used. The B-scan presentation is in rectangularcoordinates covering 180 in azimuth with the azimuth or bearing of atarget presented as the abscissa and the elevation or range of thetarget presented as the ordinate. The antenna system or spinner assemblyis rotated about a vertical axis and hence radiated signal lobe patternsare rotated to cover a horizontal plane. The angular motion of theantenna system is synchronized with and is transformed within thecathode ray tube into a linear motion of the cathode ray. In the absenceof other deflection, the presentation appears as a horizontal lineacross the lower portion of the tube screen. A uniform vertical motionfrom the bottom to the top of the tube screen and of considerablygreater rapidity is also imparted to the cathode ray. Each vertical lineon the tube screen is synchronized with the pulse transmitted from theradar set as presented in the horizontal base line. The returned echopulses are impressed upon the intensity grid of the cathode ray tube tothereby increase the intensity of the presentation of a target. Theposition of the target vertically of the tube screen indicates theelevation of the target with respect to the radar position and itsposition in azimuth is read from an azimuth scale extending along thebottom of the L tube screen. Y

In the electromagnetic type of tube from which B- scan presentations areobtained, a sweep current is caused to tiow through a pair of verticaldetiecting coils and a positioning current that is controlled by theposition of th'ieantenna in azimuth is caused to flow through a pair ofhorizontal deliecting coils. By these deecti'o'n coils, the position ofthe vertical sweep of the cathode ray is aligned with the position inazimuth of the antenna. One forni of antenna is designed to scan aregion upto '90 on either side of its normal forward position or deadahead a in the type B-scan presentation. The position dead ahead isindicated byea hair line extending vertically midway between the lateralextremities of the tube screen. In 4the type B presentation, echosignals returning from the target normally appear above the time baseline and to the right or to the left of the vertical hair line. Fromthefposition of vthe echo signals returned from a target, the azimuthand the range positions of the target with vrespect to the radarposition are obtained.

j In the obtaining of a P. P. I.scan or a plan position indicatorpresentation, an electromagnetic type of tube is used. In the obtainingof this type of presentation, the radar antenna is caused to rotateabout a vertical axis through `the f ull 360 of azimuth. The signallobes beamed from the antenna are narrow in azimuth to provide sharpreadings and are broad in elevation so that all angles in the horizontalplane are searched with each rotation of the antenna. The presentationis in polar coordinates and has the general apearance of a map of the*area swept by the radar antenna. The form of presentation providesinformation in terms of the range and bearing of targets but does notprovide information concerning `their elevation.

In the P. P. I.-scan presentation, the radar antenna position occupiesthe center of the screen. Each signal pulse thatis beamed from theantenna would appearin the presentation at the center of the tube screenif it were not blanked out to avoid burning a hole in the screen and thesweep trace starts at the center vof the screen and travels radiallyoutwardly to the peripheral edge thereof. Consecutivesweep traces movecircumferentially of the tube screen in conformity with the rotation ofthe radar antenna. a Y

The cathode ray tube used in P. P. I. presentations is intensitymodulated so that the presentations of its sweep ,traces are just at thethreshold of visibility until ampified by the arrival of echo pulsesthat increase their in- 1tensity into the range of visibility. The topof the cathode ray screen represents a directly forward position or deadahead. When the antenna is pointing dead ahead, the sweep of theelectron beam moves from lthe center 'of the screen to thektop thereof.The sweep ofethe ele'c'tron'beam is synchronized in both direction andin degree with the motion of the antenna and hence as the antenna movesfrom directly ahead toward the right, the presentation upon the tubescreen moves from directly ahead toward the right in conformity with themotion of the antenna. A polar map is developed thereby upon the tubescreen with range plotted radially against positions in azimuth plottedalong the periphery of the screen.

In the application of the present invention, A-Scan and P. P. I.=scanpresentations are available from the tube and circuit that are shown inFig. l and A-scan and B-scan presentations are available from the sametube rotated 90 in the m'dilied circuit shown in Fig. 2. The discloseddevice with minor adjustments makes it possible to obtain accurateanalysis of radar echoes in situations wherein a usual form of radar setproviding a single presentation would be entirely inadequate. Themultiple presentation provided by the present invention is particularlyof advantage where there is inadequate differentiation between a targetand its environs. Illustrative situations in which the mltiplepresentations provided by the present device 'are useful are inthelpresence of enemy jamming, or where dense` clouds or chaff obscuretargets, or where a radar set is being used 'over open water that is soturbulent that waves reflect the radar pulses and the 'echo pulses thatare returned from the waves 'are of suliicieht strength so that it isdifficult foithe operator of the radar set to distinguish a target fromthe waves around it. The multiple presentation that is provided by thepresent invention has important use'in the military iield where it iscapable of operating successfully in the presence of enemy jamming thatwould render useless a'usual radar set provided with asingle type ofpresentation, particularly since it renders electiv'e such anti-jammingmeasuresl as beat note' 'reception through enemy electronic jamming.`There has been vno single cathoderay tube for use in radar availableheretofore capable 'of presenting the multiple for'rns 'of scanpresentation that are provided by the present invention with a simplemodilic'ation of the equipment. The present invention provides improvedperformance from a single radar 'set with arni'nir'num weight andoccupied space that would require a greater plurality of radaroscilloscopes as previously available which is particularly ofimportance in the use of radar airborne equipment.

An object of the present invention is to provide a single eathode raytube that is adapted for being interchangeably inserted in eithernof twocircuits for providing multiple presentations therefrom with a minimum`of adjustment and equipment.l Y

Another object is to provide an improved cathode ray tube in circuitarrangements with which it is ypossibleto obtain easier and moredependable readings through jamming and clutter than is possible withany-previously known radar equipment.

Another object is to provide an improved cathode ray tube that isadapted for being removably inserted in either of two improved circuitsfrom which single tube either electromagnetic or Velectrostaticperformance may be obtained.

A further object is to provide a cathode ray tube and associatedcircuits that are adapted for providing 'a wider and more dependablerange of performance through the impressing of v a -gr'eater range-.ofbeam current density-through the'tubethan has been practicalinpreviously kno'wntubes of the electrostatic deec'tion'typ'e.

A further object 'is itc) provide improved radar equipment of minimum-weight and occupied space for use in airborne equipment.

Another object ist Vprovide amultiple presentation cathode ray tube andassociated circuits for improved target study and analysis.

Additional objects will be apparent to those who are informed in theelectronics ti'ell from'the'following'descrption 'of illustrativeembodir'nents of the present irivention that are shown in theaccompanying drawings wherein:

Fig. 1 is a fragmentary wiring diagram and an axially sectioned cathoderay tube shown in side elevation that together provide horizontallyextending sweep traces and normal and accentuated A-scans, together withP. P. 1.scan presentations upon the tube screen and that incorporateparts of the novel features of the present invention;

Fig. 2 is a fragmentary transverse sectional view of the tube takensubstantially along the line 2-2 of Fig. l with the background and someconnections deleted for simplicity of presentation and With the tuberotated 90 from the position in which it is shown in Fig. 1, togetherwith a modification in the cathode ray deflecting means part of thecircuit there shown for the display of vertically extending sweep tracesin normal and accentuated A-scan presentations and for the provision ofB-scan presentations upon the tube screen;

Fig. 3 is an elevational view of the screen of the cathode ray tubeshown in Fig. l with a concentric circle distance indicating screenremovably interposed between the tube screen and an observer and showingan illustrative horizontally extending A-scan presentation;

Fig. 4 is an elevational View of the screen of the cathode ray tubeshown in Fig. 1 with a concentric circle distance indicating screenremovably disposed therebefore and with a P. P. I.scan presentationappearing thereupon;

Fig. 5 is an elevational view of the screen of the cathode ray tube inthe modified circuit shown in Fig. 2, with a B-scan presentationappearing inwardly of the frame of a masking Screen that carries azimuthand distance scales along two of its intersecting edges with the maskingscreen removably interposed between the tube screen and an observer; and

Fig. 6 is an elevational view of the screen of the cathode ray tube inthe circuit shown in Fig. 2, bearing an A-scan presentation comprising avertically extending sweep trace appearing inwardly of the frame of amasking screen that bears azimuth and distance indicating scales along apair of its intersecting edges with the masking screen removablydisposed in front of the tube screen.

In Fig. l of the accompanying drawings is shown a cathode ray tube in acircuit in which the tube is adapted for providing nonnal A-scan,accentuated A-scan and r P. P. I.scan presentations as parts of thepresent invention and as accessory to a usual radar system 8. The radarsystem 8, from which components not essential to the description of thepresent invention have been deleted for reasons of simplicity, emitstransmitted pulses from its antenna 49 and receives back echo pulsesfrom metallic targets in the path of its emitted pulses. The radarsystem 8 contains radio frequency and intermediate frequency or R. F.and I. F. sections 10 to which returned echo pulses intercepted by anantenna dish 48 are applied. The returned echo pulses are passed fromthe R. F. and I. F. sections 10 to a video amplifier 9 where they areamplified and fed into a presentation circuit that forms a part of thepresent invention.

The video amplifier 9 amplifies received echo pulses and applies them toa potentiometer resistor 12 connected at one end to ground and at itsopposite end to the movable arm of a switch S5. A presentationaccentuating or contrast controlling potentiometer tap 13 is appliedadjustably along the potentiometer resistor 12. The potentiometer tap 13is connected through a capacitor 14 to the movable arm of a switch 15.The switch 15, when closed, applies the returned echo signals from thevideo amplifier 9 directly to an intensity grid 16 part of an electrongun that is mounted within a neck or stem portion 17 of an evacuatedenvelope part of the cathode ray tube that is shown in Fig. l forcausing the accentuation of the returned echo pulses in theirpresentation upon the tube screen.

In general, for all types of presentations that are con- 6 templatedhereby, when the accentuation switch 15 is open, normal presentationsappear upon the tube screen and when the switch 15 is closed, amplifiedecho pulses are applied to the intensity grid 16 that results in thepresentation of accentuated signals. In other words, the switch 15serves to connect the intensity grid 16 to a portion of the output fromthe video amplifier 9, thereby accentuating the tops of echo pulsesabove ambient noise.

The setting of the signal accentuating potentiometer tap 13 upon thepotentiometer resistor 12 varies the amount of video voltage that isapplied to the intensity grid 16 of the cathode ray tube. A bias battery18 applies direct current through a fixed resistor 22 at all times tothe tube intensity grid 16. The amount of direct current voltage that isapplied to the intensity grid 16 from the bias battery 18 may be furtherdiminished by the increased setting of an intensity controllingpotentiometer tap 2t) along the potentiometer resistor 21 across whichthe potential of the battery 18 is applied. The potentiometer resistor21 is grounded at its junction with the negative terminal of the battery1S. The adjustment of the intensity controlling tap 20 upon thepotentiometer resistor 21 preferably is such as to apply just sufficientpotential to the tube intensity grid 16 so that the presentation uponthe coating or screen 26 of the cathode ray tube is but slightly inexcess of the threshold of visibility under no signal conditions. Thesettings of the contrast controlling potentiometer tap 13 and of theintensity controlling potentiometer tap 20 should be such as to providepresentations of optimum signal visibility upon the tube screen 26.

The presentation upon the tube coating or screen 26 is accomplished bycausing it to be swept by a cathode ray 23 that is emitted by a cathode2S of the tube and that passes through the intensity grid 16 thereof.For all signal presentations that are contemplated hereby, the intensitygrid 16 operates to increase the intensity of the presentation upon thetube screen 26 with increase in the potential that is applied thereto.The tube screen 26 is disposed upon the inner surface of a at or curvedend 24 of the tube envelope and remote from a tube base 27 that carriesa desired plurality of pin contacts 29 in usual manner. A cathode ray orelectron beam 23 is concentrated sufficiently by its passage through theintensity grid 16 so that it is sufficiently narrow to also pass throughan aperture in a first anode 28 that is disposed forwardly of theintensity grid 16 in the. cathode end or stem 17 of the tube.

The tube first anode 28 is maintained at a positive potential from asuitable first anode voltage source 30 so that it accelerates to adegree directly proportional to the magnitude of the potential appliedto the first anode 28, the velocity of the electrons in the electronbeam 23. The first anode 23 operates in all types of scan that areavailable in the exercise of the present invention, to attract and tofocus the electron beam 23 so that it passes substantially along theaxis of the tube stem 17.

Further magnetic focusing the the electron beam 23 is accomplished inall types of disclosed scan by a focusing magnet 31 that is disposedforwardly of or upon the screen side of the first anode 28 and outwardlyof the tube stem 17. The focusing magnet 31 preferably is a permanentmagnet of centrally apertured ring or do-nut shape and is mounted uponthe tube stem 17 so that its disposition with respect to the axis of thetube stem is adjustable both axially and radially thereof. When soadjustable, the focusing magnet 31 can be made to assist in both thefocusing of the electron beam 23 and in causing it to be centered toflow substantially along the axis of the tube stem 17. The electron beamfocusing magnet 31 sets up and maintains a magnetic field through whichthe electron beam 23 is caused to pass. The portion of the magneticfield so established through which the electron beam 23 passes compriseslines of force that are substantially tangential to the direction oftravel of the electrons in the electron beam 23. The electron beamfocusing magnet 31 serves to concentrate, to narrow and to center theelectron beam on the axis of the tube stem 17 so that it lmay appear asa small dot upon the fluorescent screen 26 of the tube.

A pair of electrostatic sweep deecting plates 50 and 51 are disposedsubstantially parallel with respect to each other within the tube stem17 and substantially equi-distant from the axis thereof. In the circuitof the electrostatic plates 50 and S1, the plate 50 is connected throughthe coupling capacitor 11 to the fixed arm of the switch 55, to themovable arm of which returned echo pulses amplified by the videoamplifier 9 are applied. A rectifier 54 is connected across the plates50 and 51. The plates 51 and 50 through resistors 68 and 52,respectively, are connected with a high voltage source 37 of positivepotential. Plate 51 is connected through capacitor 57 to ground. Thecapacitor 11 and 57 protect the high voltage source 37 from ground.Video voltage is impressed upon plate 50 through capacitor 11 whenswitch 55 is closed. In this circuit the rectifier 54 serves the purposeof direct current restoration between the plates 50 and 51. Therectifier 54 minimizes the tendency for sweep deections of the electronbeam 23 to appear both above and below the sweep trace in a presentationupon the tube screen 26. Rectifier 54 acts as a low resistance toreturned echo pulses of one polarity amplified by the video amplifier 9when the switch 55 is closed and acts as a high resistance to pulses ofthe opposite polarity. The rectifier 54 may be a rectifying crystal or aseries of crystals, a suitable vacuum tube device or the like.

The plates 50 and 51 maintain electrostatic lines of force that extendnormal to the axis of the tube stem 17. These lines of force produce abeam deflection that is parallel to the magnetic lines of force that aremaintained by the sweep deflection coils 38 and 39 and deflect theelectron beam 23 by means of lines of force that extend perpendicular tothe faces of the electrostatic plates 50 and 51. The electron beam 23 isdeflected by these electrostatic lines of force in direct proportion totheir strength. The plates 50 and 51 impart electrostaticcharacteristics to an otherwise electromagnetic type of tube.

An electrically conducting second anode 35 imparts magneticcharacteristics to the tube for all types of presentation that are-contemplated hereby. The second anode 35 preferably comprises a coatingof conducting material disposed inwardly and axially of both the tubecylindrical stem 17 and a frusto-conical frontal portion 36 of the tubeenvelope from their junction. The tube frontal portion 36 terminates4remotely from its junction with the tube stem 17 in the transparenttube end 24 upon the inner surface of which the tube screen 26 ispositioned.

The second anode 35 has a high positive voltage applied to it, as bybeing connected with the high voltage source 37 that also supplies theplates 50 and 51, or the like. The positive charge upon the second anode35 maintains a fieldfree space within the frusto-conical frontal portion36 of the tube and serves to attract secondary electrons that areemitted by the tube screen 26, upon being impacted by the electron beam23 for all of the contemplated types of scan presentation.

The electron vbeam 23 in its sweep is deected from its normal courseaxially of the tube stem 17 and from the center of the screen 26 bysuitable means, such as by a pair of sweep defiection coils 38 and 39 orthe like, shown in Fig. 1, for .A-scan and for P. P. I.scanpresentations. .The electron beam 23, under the influence of the pair-of deection coils 38 and 39, is caused to sweep across or -between thecenter and the edge of the screen v26 along predetermined paths underthe iniiuence of electromagnetic lines .of force established by thesweep deflection c oils 3'8 and l39.

The sweep deection coils 38 and 39 are connected with and are energizedfrom a sweep generator 40, part of a sweep system of the radar system 8.The sweep generator 40 generates a saw-tooth current that is passedthrough the deflection coils 38 and 39 in usual manner. The saw-toothcurrent builds up the energization of the coils 38 and 39 to a maximumvvalue for yeach sweep of the cathode ray 23 across the tube screen 26,then drops the coil energization to a minimum value for the returnsweep, in timing the energization of the coils 38 and 39. The positionupon the tube screen 26 of the electron beam 23 in its radial sweep atany instant depends upon the polarity direction of the electromagneticfield that is determined by the physical disposition at that time of thedeflection coils 38 and 39 circumferentially of the tube stem 17.

The pair of sweep defiection coils 38 and 39 preferably are disposedcoaxially with respect to each other and are mounted for rotary motioncircumferentially of the tube stem 17 by being mounted upon a planedriven gear 41 of a large diameter and with teeth disposed along itsperiphery as shown in the accompanying drawings. The peripheral teeth ofthe driven gear 41 are engaged by peripheral teeth upon a smallerdriving gear 42. The driving gear 42 is mounted upon a shaft 43 so thatit may be rotated -mechanically by a receiver selsyn or selsyn motor 45,part of a selsyn system, or, upon the interruption of the selsyn system,manually by operation of a deection coil knob ,44.

The receiver selsyn motor 45 is connected by the 'switch 46 to atransmitter selsyn or selsyn generator 47. The selsyn generator 47 isactuated from an antenna or spin ner assembly comprising, for example, aparaboloid reflector or dish 48 and the antenna 49. The selsyn generator47 is geared through gears 58 and 59 Ato a yoke S6 that supports theantenna dish 48. The dish 48 is journalled Vin the yoke 56 by a pair ofbearings -60 that are positioned -upon the opposite ends of a commondiameter through the dish 48 so that the dish may be caused-to tilt ornod under the control of an operator of the radar set. In the :selsynsystem, the selsyn motor 45 falls into step with any movement of theselsyn generator 47 when the selsyn connecting switch 46 is closed. Awave guide designated by the lead 19 connects the antenna or spinnerassembly with the radio frequency and intermediate frequency sections 10of the radar system 8.

When the switch 46 is open so that the connection between the selsynmotor 45 and selsyn generator 47 is broken, the pulsed energization ofthe pair of coils 38 and 39 from the sweep generator 40 in an A-scanpresentation commonly causes the cathode ray beam 23 lto swing laterallyof the tube screen 26 with sufficient rapidity so that the presentationis substantially that of a straight line. When the switch 46 is closed,the rotation of the antenna spinner assembly causes the rotation of thepair of deection coils 38 and 39 around the tube stem -1'7 in a mannerthat is synchronized with the rotation of the spinner assembly andthereby causes a P. -P. I. presentation upon the tube screen 26.

v The presentation produced when the electron beam 23 strikes the tubecoating or screen 26 is viewed normally vthrough the transparent tubeend 24. Screens 61 or 62 are permanently mounted in the cathode rayvtube thousing, 61 being used for P.P.I./A scan and 62 being used forB/A scan applications. Movable screens 63 and 64 are preferably somounted as to be removably moved into or out of registration before thetube coating or screen 26. For example: screen 61 may bear a pluralityof distance indicating concentric circles to be used for P. P. I.viewing; alternatively, screen 62 may bear .a square or rectangular matfor framing the B type presentation upon the ytube screen 26; screen 63may be a blue light filter; and screen 64 may be an orange light filter.An orange light filter having a blue strip for viewing an A-scanpresentation may be used if preferred.

The tube coating 26 preferably is a multiple or dual purpose screencomposed of a plurality of layers of commonly available phosphors oi'materials that provide for the single screen both short and longpersistence performance. The use of the screens 61 to 64, respectively,are in conformity with usual practice in that when screen 61 ispositioned in front of the tube screen 26, an observer sees theplurality of concentric circles indicating upon the presentation thedistance of the target from the location of the radar set depending uponthe nearness of the image of the target to one of the concentriccircles. The concentric circles may be calibrated to indicate yards,miles or or l0 miles distances between each pair of concentric circles,in usual manner. Alternatively, for type B presentation, the dispositionof the mat screen 62 before the tube screen 26 causes the presentationto be framed within the limits of a square or rectangular mat. A pair ofadjacent edges of the mat screen 62 bear respectively, scales in azimuthand in distance, as commonly used.

The disposition of the blue color iilter 63 before the tube screen 26permits the conduction of light waves in the blue portion of thespectrum to pass through the screen or color lter and to be apparent toan observer who thereby selectively views blue ash short persistencepresentations upon the tube screen 26. The orange color lter screen 64may in a similar manner be positioned before the tube screen 26 for theconduction or transmission of light rays within the yellow, amber toorange region of the spectrum so that an observer may therebyselectively view long persistence presentations upon the tube screen 26.

It will be apparent that desired combinations among the screens 61 to 64may be used, such as combinations of the distance indicating concentriccircle screen 61 and the mat screen 62 with either of the color lterscreens 63 and 64 and the like. An A-scan presentation is commonlyviewed through a blue lter, because of its transient characteristic.Mapping presentations, such as B and P. P. I.-scan presentations, arenormally viewed through deep orange lters.

In an A-scan presentation, echo signal deflections appear in thepresentation upon the tube screen 26 substantially normally to thehorizontal sweep trace. This provision adapts the tube shown in Fig. 1for providing an A-scan presentation when the switch 46 is open. Openingthe switch 46 disconnects the selsyn motor 45 from the selsyn generator47 that is operated from the spinner assembly that carries the antenna49. Opening of the switch 46 leaves the cathode ray dei'lecting coils 33and 39 in their last established position with respect to the tube stern17 and presumably with the antenna 49 pointing directly toward thetarget for the return of echo pulses of optimum strength. For A-scanpresentations the switch 55 is closed, and knob 44 is rotated to producethe horizontal sweep position required for this type of application. Inthese A-scan presentations, the switch may be either open or closeddepending respectively upon whether a usual A or an accentuated A- scanpresentation is desired. This switching provision adapts the tube alsofor P. P. I.scan presentations upon the tube screen 26 with the tubepositioned as shown in the circuit in Fig. l.

The type of presentation desired from the tube in the circuit shown inFig. l is obtained by operation of the switches 15, 55 and 46, which canbe ganged together to simplify switching operations where P. P. I. andA-scan are used in the absence of accentuated A-scan. Operatively, whenswitches 15 and 55 are open, amplied echo pulses coming from the videoamplier 9 are passed through the resistor 12 to ground. When the switch15 is closed and switch 55 is open, these ampliiied echo pulses arepassed through the coupling capacitor 14 to the intensity grid 16against the resistance of the potentiometer resistor 12. When switch 15is opened and switch 55 is closed, the amplified echo pulses applied tothe coupling capacitor 11 are impressed across the capacitor couplingplates and 51 against the resistance of the potentiometer resistor 12.When the switch 46 is opened, the disposition of the cathode raydeflecting coils 3S and 39 with respect to the tube stem 17 isestablished by operation of the detlection coil knob 44. When the switch46 is closed, the selsyn system thereby connected causes the pair ofcathode ray deecting coils 38 and 39 to follow in direction and degreeany rotation of the spinner assembly of which the antenna 49 is a part.

In the operation of the tube and circuit arrangement shown in Fig. 1,pulsed signals originate within the radar system 8 and are conductedthrough the wave guide indicated by the lead 19 to the radar antenna 49from which they are beamed into space in `a lobe pattern. The signals soradiated are reflected in diminished energy content as an echo pulse bya metallic object such as an airplane,

` battleship or the like within the lobe pattern. The echo pulse isintercepted by the antenna dish 48 and is fed into the wave guide lead19 which conducts the echo pulse and applies it to the IF and RFsections 10 of the receiver part of the radar system 8.

The azimuth position of the antenna 49 at the instant the echo isreceived controls the disposition of the cathode ray deflecting coils 38and 39 when the switch 46 is closed to connect the selsyn system,comprising the selsyn generator 47 and selsyn motor 45. When a target islocated in this manner, the switch 46 may then be opened and the switchclosed and an optimum presentation of the target be made upon the tubescreen 26 by drawing an angular presentation at the azimuth position ofthe target to the horizontal position by operation of the cathode raydeflection coil knob 44. With these minor adjustments, a normal A-scantarget presentation appears as a vertical pip upon a horizontallyextending sweep trace upon the tube screen 26 when the switch 15 is openand an accentuated A-scan presentation appears upon the tube screen 26when the switch 15 is closed.

In using the invention for A-scan presentation, the antenna 49 is atrest and beams radar energy directly toward the target for maximumstrength of echo pulse presentation. With the switch 15 open and switch55 closed, the amplied echo pulse from the video amplifier 9 is deectedby the resistor 12 through the closed switch 55 and is impressed throughcoupling capacitor 11 upon resistor 52, the electrostatic sweepdeflecting plate 50 and the direct current restoration rectier 54. Thecomplete video wave is applied to the plate 50 and a rectified componentof the wave is applied to the plate 51. This application of theamplified echo pulse to the pair of plates 50 and 51 causes a pip ordeection normal to the direction of the sweep trace upon the tube screen26 from which a reading may be taken indicating the distance of thetarget from the radar position. When the cathode ray tube is mounted asshown in Fig. 1 of the drawings, the deecting coils 38 and 39 providethe horizontal sweep and the electrostatic plates 50 and 51 providevertical deections of the sweep when echo signals are impressedthereupon and when switch 46 is open, switch 55 is closed and switch 15either open or closed, depending upon whether plain or accentuatedA-scan is desired, respectively.

For an accentuated A-scan presentation, switch 15 s closed, switch 55 isclosed and switch 46 is open. With switch 15 closed, the power carriedby the amplified echo pulse impressed upon the coupling capacitor 14 andconducted through the switch 15 to the tube intensity grid 16 augmentsthe potential normally supplied from the battery 18 to the intensitygrid 16 to draw an increased quantity of electrons from the tube cathode25 and thereby accentuate the A-scan presentation upon the tube screen26.

For a plan position indicator or a P. P. I.-scan presentation upon thetube screen 26 in the circuit that is shown in Fig. l, switch 15 isclosed, switch 55 is opened and switch 46 is closed. The power of anamplied echo signal impressed upon the coupling capacitor 14 and of amagnitude depending upon the setting of the tap 13 upon thepotentiometer winding 12 and augmented by the potential of the battery18, depending upon the setting of the tap upon the resistor 21, isimpressed upon the intensity grid 16 for intensifying the image of atarget appearing in the presentation upon the tube screen 26.

In the P. P. I.-scan presentation, switch 46 is closed so that movementof the spinner assembly under the control of the radar operator actuatesthe selsyn generator 47 lfollowed by the selsyn motor 45. The selsynmotor .causes the cathode ray deection coils 38 and 39 to be rotatedabout the tube stern 17 through the gear train comprising the gears 42and 41. In this usual operation of the deection coils 38 and 39, thesweep of the cathode ray 23 upon the tube screen 2 6 is synchronizedaccu- `:rately with the rotation of the spinner assembly with the usualarrangement of selsyn phasing switches. When the antenna spinnerassembly is rotated through 360, the cathode ray deflecting coils 38 and39 undergo a complete rotation through 360 around the tube stem 17. Thisrotation of the deection coils 38 and 39 together with the operation ofthe sweep generator 40 deflects the sweep trace of the cathode ray 23upon the center of the tube screw 26 through 360 around the tube screen26.

In this manner the deflection coils 38 and 39 are displacedcircumferentially of the cathode ray tube stem 17 in conformity with therotation in azimuth of the antenna 49.

The .circumferential movement of the deflection coils 3S and 39 aroundthe tube stem 17 causes the cathode ray 23 to sweep the screen 26 fromthe center to the peripheral edge thereof continuously and to follow .orto move circumferentially of the screen 26 in conformity with the motionin azimuth of the antenna 49 in usual manner for a P. P. I-scanpresentation, such as that shown in Fig. 4 of the accompanying drawings.When using the P. P. I.-scan presentation, an investigation is beingmade of the direction in which the antenna 49 is pointing when a targetis located with the antenna 49 Vcontinuously rotating and with theswitch 46 closed so that the deetcion coils 38 and 39 rotate in bothdirection and degree along with the rotation of the antenna 49. I

In the above described manner, the present invention makes available toa radar operator with the cathode ray tube positioned within the circuitshown in Fig. l, 'both I normal and accentuated A-scan presentationswith the switch closed and the switch 46 open and with the switch 15open or closed respectively, and also a P. P. I. scan presentation withswitch 46 closed and with switch 55 open and with switch 15 closed toobtain optimum visibility of the presentation upon the tube screen 26.

In Fig. 2 of the accompanying drawings is shown in fragmentary form acombined A .and B-scan application of the present invention to a systemthat is modified to the extent of using an azimuth potentiometer andstationary vcathode ray deecting coils through which polyphase currentsare passed, which assembly is to replace .the selsyn system andmechanically rotated deection coils 3S and 39 that are shown in Fig. l.The same cathode ray tube that is shown with its electrostatic sweepdeiiecting plates 50 and 51 disposed horizontally in Fig. l, is used inthe circuit illustrated in Fig. 2 rotated 90 from its position in Fig.l, so that the plates 50 and 51 are disposed vertically in the modifiedcircuit shown in Fig. 2. The same Acathode ray tube and .its previouslyrecited connections apply to the circuit in both Figs. l and 2.lComponents in Fig. 2 that correspond to components in Fig. l :bear thesame or corresponding numerals primed. The vertical disposition of lthe.electrostatic lplates 50 and 51 within the tube stem 17 results in asweep trace presentation upon the tube screen 26 that extends verticallythereof and that is deected in horizontally extending pips by each echopulse that is returned to the radar set from a metallic object.

In Fig. 2, the antenna or spinner assembly of which the antenna 49 is apart is mounted and rotated in azimuth along with the rotation of thegears `59 and 5 8. The gear 58 is connected by a shaft 73 to the midpoint of an insulating bar 74 that is adapted for rotary motion alongwith the rotation of the gear 58. The insulating bar 74 carries a pairof contacts 75 and 76 at its opposite ends. The pair of contacts 75 and76 make continuously wiping engagement with a stationary resistorwinding 77 of a rheostat or circular azimuth potentiometer. A battery 78is connected to apply its potential to two fixed taps 180 apart acrossthe potentiometer winding 77. The potentiometer moving arm comprisingthe insulation bar 74 and pair of contacts 75 and 76, is adapted torotate completely around the potentiometer stationary winding 77 in bothdirection and in degree with the rotation of the antenna spinnerassembly. The potentiometer contacts 75 and 76 through a switch 46 areconnected in series to a pair of coaxial stationary windings 80 and 81upon diametrically opposite sides of the tube stem 17. In this circuitupon the closing of switch 46', potential from battery 7 8 is passedthrough the coaxial windings 80 and 81 for controiling the dispositionof the cathode ray 23 upon the tube screen 26 in conformity with thedisposition of the contacts 75 and 76 upon the potentiometer winding 77.

In the operation of the azimuth potentiometer to which current frombattery 78 is applied to vertically iixe'd taps, if the spinner assemblyis turned so that the potentiometer moving arrn is horizontally disposedfor a position dead ahead, then no current iiows into `deflection coilsSi) and 81 and the cathode ray 23 is disposed at the center of the tubescreen 26. If the spinner assembly is turned so that the antenna 49 isdirected 90 to the right of the dead ahead position, then the cathoderay 23 is deflected a maximum amount to one side of the tube screen 26.If the antenna 49 is directed to the left of its dead ahead position,then the potentiometer contacts 75 and 76 reverse their polarity intheir engagement of the fixed taps from the battery 78 upon thepotentiometer winding 77 and the electron beam 23 is deflected a maximumamount in the opposite direction upon the tube screen 26. A sweep traceis maintained continuously upon the tube screen 26 by a pair ofcoaxially disposed sweep deecting coils 82 and 83 that are connected inseries between the sweep generator 40 and ground on dimetricallyopposite sides of the tube stem 17 and having their common axis normalto the axis that is common to the sweep deflection coils 80 and 81. Inother circuit details, the circuit -arrangements shown in Figs. 1 and 2are the same.

A presentation upon the tube screen 26, using the circuit shown in Fig.2, may be either a normal or an accentuated A-scan with the switch 46open to deenergize the pair of coils Si) and v81 and the switch 55closed, or it may be a B-scan presentation with the switch 46 closed andthe switch 55 open. As in the description of the circuit shown in Fig.l, a normal A-scan is provided with the switch 15 open and anaccentuated A-scan is provided with the switch 15 closed. In thepresentation from the `circuit shown in Fig. l, .the A-scan -sweep tracewhen adjusted by knob 44 is disposed horizontally ,upon the tube screen26. In the presentation from :the circuit shown in Fig. 2, the A-scansweep trace upon the tube screen 26 extends vertically.

In the B-.scan presentation, the azimuth potentiometer provides theazimuth position of the vertical sweep :and may be disconnected fromVthe circuit ,and replaced by .a

- fixed resistor combination adjusted to produce .a .ver-tical lf3 tracein the center of the tube corresponding to azimuth zero or dead ahead.Plates Sil and 51 would then be used in a manner similar to theirfunction when used for an A-scan or a P. P. I.scan presentationexcepting that in the A-scan, the echo deections would now extendhorizontally from a vertically extending trace.

In Figs. 3 and 4 of the accompanying drawings, presentations that areavailable to the radar operator from the circuit that is shown in Fig. land with the cathode ray tube disposed in the circuit as shown thereinare illustrated. The presentation in Fig. 3 illustrates a representativeA-scan presentation. The presentation shown in Fig. 4 represents a P. P.I.scau presentation.

Figs. 5 and 6 represent presentations upon the tube screen 26 that areobtainable from the circuit and the tube positioning that is shown inFig. 2 of the aecompanying drawings. In Fig. 5, a B-scan presentation isillustrated and in Fig. 6 an A-scan presentation is shown. In thepresentations illustrated in both Figs. 3 and 4 of the drawings, theconcentric circle bearing distance indicating screen 6i is disposed infront of the tube screen 26. In Figs. 5 and 6, the presentation isframed by the interposition of the mat screen 62 between the observer 0fthe tube screen 26. As previously indicated, the mat screen 62 bears anazimuth scale along its lower edge and a distance scale along a verticaledge, as shown.

In the normal A-scan presentation that is shown in Fig. 3 of theaccompanying drawings, a sweep trace 85 begins at the center S6 of thescreen 26 and extends to the peripheral edge thereof. If it is desiredthat the sweep trace 8S extend completely across the screen 26, theamplitude of the sweep voltage from the sweep generator 4t) is increaseduntil that result is accomplished.

When radar pulses are beamed from the radar antenna 49, or the antenna49', and the respective sweep generators 40, or begin the energizationof their pair of coils 3S and 39 or 32 and 83, respectively, if a targetis nearby, echo pulses return quickly and if the target is at a greaterdistance away, a proportionally greater length of time elapses betweenthe sending out of the radar pulse and the receiving of an echo pulse atthe radar position. The sweep generators 4t? and 40' are synchronizedwith the sources of the radiated pulses. Consequently, when an echopulse returns to the radar position, the displacement of the echo pulseupon the sweep trace with respect to the position on the sweep trace ofthe original pulse, or the start of the sweep, is a function of thedistance between the radar position and the target.

With the cathode ray tube mounted in the circuit shown in Fig. l of thedrawings, the P. P. I. presentation may extend radially of the tubescreen 26 in any position of azimuth since the cathode ray deilectingcoils 3S and 39 rotate about the tube stem 17 with the rotation of theantenna 49 in azimuth when the switch 46 is closed. For an A-scanpresentation, when the radar operator observes an echo signal upon thetube screen 26, he positions the antenna 49 directly toward the target,takes its azimuth position from the presentation, opens the switch 46and draws the sweep trace to the horizontal position by operation of thedeflection coil knob 44. Where trace rotation is secured by iieldrotation in stationary coils, horizontal sweep can be secured byswitching in proper voltages from a multiphase source to produce thehorizontal sweep action.

In the illustrative trace shown in Fig. 3, the sweep trace 85 extendshorizontally upon the tube screen. In the presentation shown with thescreen 61 in front of the tube screen 26, the trace 85 extends from thecenter of the tube screen 26 to the right hand peripheral edge thereofand shows two target pips 87 and SS as vertical deilections of thehorizontally disposed trace SS indicating ships 93 and 93 shown in Fig.4. Signal beamed from the antenna 49 is blanked out of the presentationupon the tube screen to avoid burning a hole in the screen materialsince each pulse beamed from the antenna 49 would appear in thepresentation at the tube screen center 86 and the coating would notcontinue to function if it were subjected to this continuous bombardmentat a single point. The iindings from the presentation shown in Fig. 3,assuming the concentric lines 65, 66 and 67 to be spaced in multiples ofve miles from the radar position at the screen center S6, the targetsillustrated by the pips S7 and 88 are approximately ten and eighteenmiles, respectively, from the antenna position. Azimuth position is thatwhich was indicated by the trace during P. P. I. operation.

In the presentation shown in Fig. 4 of the accompanying drawings, thesame concentric circle distance indicating screen 61 is interposed infront of the tube screen 26. In this presentation the switch 46 isclosed so that the presentation is substantially that of a map since therotating cathode ray deflecting coils 3S and 39 are caused tocontinuously rotate with the antenna 49. The rotation of the cathode raydeflecting coils 38 and 39 causes the sweep trace 9i) to continuouslyrotate between the center 86 of the tube screen 26 and the peripherythereof along with the rotation of the radar antenna 49. In thispresentation, as before, individual signals beamed from the antenna 49are blanked out of the presentation upon the tube screen 26 butseparately initiate each trace that appears thereupon, to provide the P.P. I.scan presentation that is shown in Fig. 4. In the presentationshown in Fig. 4, a body of land 91, an island 92 and two ships 93 and 93appear as radar echo areas in the adjoining water area 94. In thispresentation, the position in azimuth of dead ahead is zero degrees andthe azimuth of the ship 93, which might be regarded as a possibletarget, is indicated by the dashed line 95 as being substantially 230.The range of the ship 93 is as indicated in the drawing and, againassuming the concentric circles 65, 66 and 67 to be spaced ve miles fromeach other, would be ten miles and would be measured radially on thetube screen 26 from the center S6 thereof, which in this presentation isthe radar position. The presentation of the ships 93 and 93 in Fig. 4conforms with the pips 87 and 88 in Fig. 3. As previously stated, thepresentations shown in Figs. 3 and 4 of the accompanying drawings areavailable to a radar operator with the cathode ray tube positioned andconnected as shown in Fig. 1 of the accomy panying drawings.

With the cathode ray tube rotated and mounted in the circuit shown inFig. 2, the types of presentation shown in Figs. 5 and 6 of theaccompanying drawings are available to the operator of the radar set. Anillustrative B-scan presentation is shown in Fig. 5 and a verticallyextending accentuated A-scan presentation is shown in Fig. 6 of thedrawings. In both of these views the mat screen 62 carrying the hairline 84 is in front of the tube screen 26.

In the B-scan type of presentation shown in Fig. 5, the initial signaltrace 96 extends horizontally of the tube screen 26 that preferably hasthe mat screen 62 positioned in front of it. The mat screen 62 carries adead ahead position indicating vertically extending hair line 84 at 0azimuth. In this B-scan presentation the signals beamed from the radarantenna 49 appear in the sweep trace 96 that preferably extendssubstantially parallel with and slightly above the azimuth scaleextending along the horizontal lower edge of the orice in the mat screen62 as shown. A distance scale extends vertically along the lateral edgeof the orifice in the mat screen 62, as shown, and, with reference tothe trace 96, indicates the distance of the target from the antennaposition. In this presentation land 97 and an island 98 appear as beingradar echo areas distinct from the water area 99. In this respect, theB-scan presentation resembles the P. P. I.scan presentation shown inFig. 4. The azimuth position of zero degrees at which the hair line 84appears illustrates the position dead ahead from the antenna positionand the azimuth scale is limited to a position plus 90 to the right ofdead ahead and negative 90 to the left of dead ahead. In thispresentation the radar antenna scan is limited to a straight angle or180 in front of and to either side of the radar position. The positionin azimuth and range or distance of a target, such as the island 98,from the antenna position is readily indicated from the scales appearingupon the mat screen 62.

The presentation shown in Fig. 6 of the accompanying drawings is alsoavailable to the operator of the radar set with the assembly shown inFig. 2, and here again the mat screen 62 is positioned in front of thetube screen 26. In this presentation, switch 1S is preferably closed andswitch 46 is open. The positioning of the cathode ray tube with theelectrostatic plates 50 and 51 disposed vertically results in thevertical trace 190, as shown. Deflections of the sweep trace 100 such asthe deflection 101 indicates the presence of the land 97 shown in Fig. 5as being dead ahead of the antenna position. Other deliections may be tothe right or left of the hair line 84, as indicated by the position of atarget projected upon the azimuth scale extending along the lower edgeof the mat screen 62. The target range would be at a distance from theantenna position that is indicated upon the distance scale that extendsvertically along the right; hand edge of the orifice in the mat screen62. The closing of the switch 15 causes the impression of the returnedecho signals upon the intensity grid 16 of the cathode ray tube andprovides a presentation of optimum intensity upon the tube screen 26.y

From the foregoing description, it will be apparent that with a singlecathode ray tube when mounted in the circuit shown in Fig. 1, the radaroperator has available to him a P. P. I.-scan presentation and hischoice of a normal A-scan presentation or an accentuated A-scanpresentation beginning at either the center of the cathode ray tubescreen or extending diametrically thereof depending upon the nature ofthe potential that he applies to the cathode ray deecting coils 38 and39. In the presence of enemy jamming through which enemy signals makeuseless a P. P. I. presentation, the radar operator by a switchmanipulation has immediately available to him an A-scan presentationwhich, depending upon the nature of the enemy jamming, might provide himwith the nature and range of an intended target, which data could notpossibly be obtained under those circumstances from a P; P. I.presentation. Within the further exercise of the present invention, theradar operator, by simply withdrawing the cathode ray tube from thecircuit shown in Fig. 1, rotating it 90 and inserting it in the slightlymodified circuit shown in Fig. 2, then has available to him the choiceof a B-scan presentation and either a normal or theaccentuated A-scanpresentation such as those that are shown in Figs. 5 and 6,respectively, of the accompanying drawings.

It will be noted that the particular details of the cathode ray tubethat is shown in the accompanying drawings and of the particularcircuits with which it is associated have been submitted for thepurposes of illustrating and describing suitable operative embodimentsof the present invention and that similarly functioning changes ormodiiications may be made therein without departing from the scope ofthe present invention.

I claim:

1. A cathode-ray tube multiple presentation system for use with atransmitter-receiver system comprising an antenna spinner systemconnected by a wave guide t0 the radio frequency and intermediatefrequency sections of the transmitter-receiver system and the antennaspinner system connected through an interruptible selsyn system to acathode ray deflecting rotatable means mounted toA move insynchronization with the antenna spinner assembly around the stem of thecathode ray tube whereina cathode emits an electronV beam toward ascreen with the cathode ray deecting means timed in the sweep of thecathode ray over the tube screen from a sawtooth wave emitted from asweep generator part of the transmitter-receiver system, the cathode raytube multiple presentation system comprising in combination with theabove designated components an intensity grid mounted forwardly of thetube stem and adjacent the cathode therein, a lirst anode forwardly ofthe intensity grid within the tube stem for increasing the velocity ofthe electron beam, a first magnet adjustable axially and radially of thetube stem and mounted outwardly thereof and forwardly of the first anodefor maintaining electromagnetic lines of force extending substantiallytangentially to the direction of liow of electrons in the electron beamto thereby narrow the electron beam toward the axis of the tube stem, apair of electrostatic electron beam deiiecting plates disposed forwardlyof said lirst magnet and maintained at a high positive potential and towhich beam deflection plates echo signal from the radio frequency andintermediate frequency sections of the transmitter-receiver system maybe selectively applied directly or in parallel with echo signalapplication to the said intensity grid of the cathode ray tube, arectiier connecting said pair of electrostatic plates, a resistorconnecting said pair of electrostatic plates in parallel with saidrectifier, a deiiection coil knob operating a part of said selsyn systemand for manually adjusting said magnetic cathode ray deflecting meansupon the interruption of the selsyn system, and switch means forinterrupting the selsyn system.

2. A radio signal presentation device for use in a transmitter-receiversystem, comprising a radar system initiating signals, an antennaassembly transmitting and receiving said signals, anelectromagnetic-electrostatic cathode ray tube containing electrodes anda screen and connected with said radar system and said antenna assemblyfor providing signal presentations, contrast controlling iirst variableresistor means connected between said radar system and a signalreceiving rst electrode in said tube, intensity controlling secondvariable resistor means connected between said signal receiving iirstelectrode in said tube and ground, a first switch means connectedbetween said iirst and second resistors, a first electrostatic sweepdeflection plate within said tube, a second switch means capacitivelyconnected between said radar system and said first deflection plate, asecond electrostatic deflection plate positioned within said tube, asignal focusing permanent magnet positioned between the said firstelectrode and said pair of plates, a voltage source supplying voltage toboth of said plates, rectifier means connected between said plates,sweep deflection coils positioned between said pair of plates and thetube screen, and means adjusting said deflection coils circumferentiallyof said tube.

3. The device described in claim 2 with a third switch means releasablyconnecting the means for adjusting said sweep deliection coilscircumferentially of said tube in its relation with the operation ofsaid antenna assembly.

4. The device described in claim 2 wherein said deflection coiladjusting means is a selsyn system between said antenna assembly andsaid sweep deflection coilS for positioning said sweep deflection coilscircumferentially of said tube in a predetermined relation with thesetting of said antenna assembly.

5. A radio system presentation device for use in a transmitter-receiversystem, comprising a radar system initiating signals, an antennaassembly transmitting and receiving said signals, anelectromagnetic-electrostatic cathode ray tube containing electrodes anda screen and connected with said radar system and said antenna assemblyfor providing signal presentations, contrast controlling rst variableresistor means connected between said radar system and a signalreceiving first electrode in said tube, intensity controlling secondvariable resistor means connected between said signal receivingv lirstelectrode in said tube and ground, a first switch means Connectedbetween said first and second resistors, a first electrostatic sweepdeection plate within said tube, a second switch means capacitativelyconnected between said radar system and said first defiection plate, asecond electrostatic sweep deliection plate positioned within said tube,a signal focusing permanent magnet positioned between said firstelectrode and said pair or" plates, a voltage source supplying voltageto both of said plates, rectifier means connected between said plates,sweep defiection coils positioned between said pair of plates and thetube screen, and a sweep deection coil adjusting knob for altering theposition of said switch deflection coils with respect to said tube.

6. A radio system presentation device for use in a transmitter-receiversystem, comprising a radar system initiating signals, an antennaassembly transmitting and receiving said signals, anelectrornagnetic-electrostatic cathode ray tube containing electrodesand a screen and connected with said radar system and said antennaassembly for providing signal presentations, contrast controlling firstvariable resistor means connected between said radar system and a signalreceiving first electrode in said tube, intensity controlling secondresistor means connected between said signal receiving first electrodein said tube and ground, a first switch means connected between saidfirst and second resistors, a first electrostatic sweep deection platewithin said tube, a second switch means capacitatively connected betweensaid radar system and said first deflection plate, a secondelectrostatic sweep deflection plate positioned within said tube, asignal focusing permanent magnet positioned between said first electrodeand said pair of plates, a voltage source supplying voltage to both ofsaid plates, a direct current restoration rectifier connected betweensaid plates, resistor means connected between said plates, sweepdeliection coils positioned between said pair of plates and the tubescreen, and means adjusting said deflection coils circumferentially ofsaid tube with respect to the setting of said antenna assembly.

7. A radio signal presentation device for use in a transmitter-receiversystem, comprising a radar system intiating signals, an antenna assemblyof a rotatable yoke carried dish and dipole for transmitting andreceiving said signals, an electromagnetic-electrostatic cathode raytube envelope including a stem and containing electrodes and a screenand connected with said radar system and said antenna assembly forproviding signal presentations, contrast controlling first variabieresistor means connected between said radar system and a signalreceiving electrode in said tube, intensity controlling second variableresistor means connected between said signal receiving electrode in saidtube and ground, a first switch means connected between said first andsecond resistors, a first electrostatic sweep deflection plate withinsaid tube, a second switch means capacitatively connected between saidradar system and said first deection plate, a second electrostatic sweepdeflection plate positioned within said tube, a signal focusingpermanent magnet positioned between said first electrode and said pairof plates, a voltage source supplying voltage to both of said plates,rectifier means connected between said plates, sweep generator meanswithin said radar system, circular azimuth potentiometer means having acircular resistor wiped by a pair of contacts on opposite ends of aninsulating bar rotated with the rotation of said antenna, a rst pair ofcoaxial sweep deflection coils with their common axis normal to the axisof the stem of said tube and electrically shuntng the potentiometerwiping contacts, a second pair of coaxial deflection coils with theircommon axis normal to the axis of the stem of said tube and displaced aquadrant around the tube stem from said first pair of coaxial defiectioncoils and connected between said sweep generator in said radar systemand ground, and a potential applied to the potentiometer circularresistor at the opposite ends of a common diameter thereacross.

References Cited in the tile of this patent UNITED STATES PATENTS2,059,004 Leeds Oct. 27, 1936 2,212,640 Hogan Aug. 27, 1940 2,223,983Beers Dec. 3, 1940 2,313,819 Gray Mar. 16, 1943 2,336,837 Bedford Dec.14, 1943 2,407,905 Rose Sept. 17, 1946 2,409,462 Zworykin Oct. 15, 19462,416,199 Nagel Feb. 18, 1947 2,418,487 Sproul Apr. 8, 1947 2,419,205Feldman Apr. 22, 1947 2,422,975 Nicholson I une 24, 1947 2,425,330Kenyon Aug. 12, 1947 2,426,182 De Lange Aug. 26, 1947 2,426,217Hoisington Aug. 26, 1947 2,431,990 Craib Dec. 2, 1947 2,442,975Grundmann June 8, 1948

